Tanning aids with a high protection factor

ABSTRACT

The present invention relates to tanning aids, comprises a polymethyl methacrylate shaped body, where the transparency of the polymethyl methacrylate shaped body at 380 nm is at least 40%, and the polymethyl methacrylate shaped body comprises 0.005 to 0.1% by weight, based on the weight of the polymethyl methacrylate shaped body, of at least one triazine compound according to formula (I)  
                 
in which 
         R is halogen, C 1 -C 22 -alkyl, C 1 -C 22 -alkoxy, C I -C 22 -hydroxyalkoxy, C I -C 22 -alkoxyalkyl, —NHR 1 —, —N(R 1 ) 2 , or a radical of the formula (Ia)  
                 
   X 1 , X 2  and X 3 , 
           independently of one another, are —CONHR 1 , —NR 2 R 3 , —SO 2 R 4 , —CN, —COR 5  or —COOR 6 ,    R 1  is hydrogen, C 1 -C 22 -alkyl, C 6 -C 20 -aryl, C 7 -C 20 -aralkyl, C 5 -C 8 -cycloalkyl, or a radical of the formula (Ib)  
                 
in which 
               A 1  is C I -C 8 -alkyl, C 5 -C 6 -cycloalkyl, C 6 -C 20 -aryl, C 7 -C 20 -aralkyl; and    m 1  is 1 to 10,    
               R 2  and R 3 , independently of one another, are hydrogen, C I -C 22 -alkyl, C 6 -C 8 -cycloalkyl, C 6 -C 20 -aryl, C 7 -C 20 -aralkyl, a radical of the formula (Ib) or a radical of the formula —COR 1 ;    R 4  is hydrogen, C I -C 22 -alkyl, C 6 -C 8 -cycloalkyl, C 6 -C 20 -aryl, C 7 -C 20 -aralkyl, a radical of the formula (Ib) or a radical of the formula —NR 2 R 3 ;    R 5  and R 6 , independently of one another, are hydrogen, C I -C 22 -alkyl, C 6 -C 8 -cycloalkyl, C 6 -C 20 -aryl, C 7 -C 20 -aralkyl or a radical of the formula (Ib);    
           X 4 , X 5  and X 6 , independently of one another, are hydrogen or hydroxyl.

The present invention relates to tanning aids with a high protectionfactor which comprise a polymethyl methacrylate shaped body.

A slightly tanned skin is a sign of holiday and health. In order to tanthe skin, sunscreen creams and the like are usually used as tanning aidsin order to protect the skin against damage by UV radiation. Adisadvantage of these auxiliaries is that such creams can triggerallergies in sensitive people. Furthermore, many of these substances arenot water-resistant. Accordingly, they are removed during bathing, andare then not applied again. This negligence can easily lead to skindamage.

Moreover, devices are known which bring about tanning of the skin withthe help of incorporated UV emitters. Also known in this connection arelying devices for solaria applications made of PMMA, which compriselarge amounts of UV stabilizers and/or UV absorbers in order to protectthe plastic against degradation by UV radiation. Tanning with sunlightis not possible here, however. A disadvantage of such devices is thehigh energy consumption of the UV emitters. Moreover, theseinstallations are not intended for operation outdoors, meaning thattanning is more likely to be perceived as boring.

In view of the prior art given and discussed here, it was consequentlyan object of the present invention to provide tanning aids which can beused to achieve natural tanning of the skin using sunlight without theskin coming into contact with sunscreen cream.

Moreover, it was an object of the present invention to provide a tanningaid which is particularly easy to maintain.

A further object of the invention was that the tanning aids have highdurability, in particular high resistance to UV irradiation orweathering.

Furthermore, the object underlying the invention was to provide tanningaids which can be produced in a particularly simple manner. Thus, forthe production of the tanning aids, it should be possible, inparticular, to use substrates which are obtainable by extrusion,injection moulding, and by casting processes.

A further object of the present invention was to provide tanning aidswhose sun protection can be adjusted in a particularly simple manner.For example, it should be possible to adjust the time spent under thetanning aid to a pregiven time for many skin types. With regard toclassical sunscreen cream, it should be possible to adjust these tanningaids accordingly to a certain sun protection factor.

Moreover, it should be possible to adapt the tanning aids of the presentinvention in a particularly simple manner to different requirements andapplications. Thus, for example, portable screens and built-in roofsshould be available. In this connection, it should be possible to adaptthe tanning aids to the requirements in a simple manner with respect tosize and shape.

These objects and others which, while not specified in terms of words,can be derived quite naturally from the connections discussed herein orarise automatically from these, are achieved by the tanning aidsdescribed in claim 1.

Advantageous modifications of the tanning aids according to theinvention are protected in the dependent claims which relate back toclaim 1.

As a result of the fact that the tanning aid comprises a polymethylmethacrylate shaped body, where the transparency of the polymethylmethacrylate shaped body at 380 nm is at least 40%, and the polymethylmethacrylate shaped body comprises 0.005 to 0.1% by weight, based on theweight of the polymethyl methacrylate shaped body, of at least onetriazine compound according to formula (I)

in which

-   -   R is halogen, C₁-C₂₂-alkyl, C_(I)-C₂₂-alkoxy,        C_(I)-C₂₂-hydroxyalkoxy, C_(I)-C₂₂-alkoxyalkyl, —NHR₁—, —N(R¹)₂,        or a radical of the formula (Ia)    -   X¹, X² and X³,        -   independently of one another, are —CONHR¹, —NR²R³, —SO₂R⁴,            —CN, —COR⁵ or —COOR⁶, in which        -   R¹ is hydrogen, C₁-C₂₂-alkyl, C₆-C₂₀-aryl, C₇-C₂₀-aralkyl,            C₅-C₈-cycloalkyl, or a radical of the formula (Ib)            -   in which            -   A₁ is C_(I)-C₈-alkyl, C₅-C₆-cycloalkyl, C₆-C₂₀-aryl,                C₇-C₂₀-aralkyl;            -   and            -   m₁ is 1 to 10,        -   R² and R³, independently of one another, are hydrogen,            C_(I)-C₂₂-alkyl, C₆-C₈-cycloalkyl, C₆-C₂₀-aryl,            C₇-C₂₀-aralkyl, a radical of the formula (Ib) or a radical            of the formula —COR¹ ;        -   R⁴ is hydrogen, C_(I)-C₂₂-alkyl, C₆-C₈-cycloalkyl,            C₆-C₂₀-aryl, C₇-C₂₀-aralkyl, a radical of the formula (Ib)            or a radical of the formula —NR²R³;        -   R⁵ and R⁶, independently of one another, are hydrogen,            C_(I)-C₂₂-alkyl, C₆-C₈-cycloalkyl, C₆-C₂₀-aryl,            C₇-C₂₀-aralkyl or a radical of the formula (Ib);    -   X⁴, X⁵ and X⁶, independently of one another, are hydrogen or        hydroxyl,

it is surprisingly possible to provide a tanning aid with the help ofwhich natural tanning with sunlight is possible without the skin cominginto contact with sunscreen cream.

The measures according to the invention achieve, inter alia, inparticular the following advantages:

-   -   The tanning aids according to the invention make tanning outside        possible.    -   Furthermore, it is possible to dispense with energy-intensive UV        emitters during tanning.    -   The tanning aids according to the invention are easy to maintain        and easy to produce. Thus, it is possible, in particular, to use        shaped bodies which are obtainable by extrusion, injection        moulding and casting processes.    -   The tanning aids are weathering-resistant and, in particular,        resistant to UV radiation. Furthermore, the tanning aids        according to the invention have very good mechanical properties.    -   Furthermore, the tanning aids according to the invention can be        adapted easily to very diverse requirements. Thus, it is        possible to produce, in particular, transportable screens or        solid roofs in any size in order to permit natural tanning of        the skin without having to worry about skin damage as a result.    -   Moreover, the tanning aids can be produced for each skin type,        meaning that different durations outside can be provided.

For the purposes of the present invention, the term tanning aid means adevice which comprises at least one polymethyl methacrylate shaped bodywhich can be brought between the sunlight and a skin surface to betanned. Accordingly, these may, in particular, be transparent roofs ofbuildings or screens which are, for example, immovably fixed. Moreover,roofs which can be fixed to boats, in particular paddle boats, electricboats and the like, are suitable as tanning aids.

Moreover, however, they may also be transportable screens which,depending on the thickness of the polymethyl methacrylate shaped body,are fixed in terms of their dimensions, or which can also be collapsedand stored.

The tanning aid according to the invention comprises a polymethylmethacrylate shaped body. Polymethyl methacrylate (PMMA) is known per sein the specialist field. The polymethyl methacrylate shaped bodypreferably comprises at least 30% by weight, based on the weight of thepolymethyl methacrylate shaped body, of polymethyl methacrylate.

Polymethyl methacrylates are generally obtained by free-radicalpolymerization of mixtures which comprise methyl methacrylate. Ingeneral, these mixtures comprise at least 40% by weight, preferably atleast 60% by weight and particularly preferably at least 80% by weight,based on the weight of the monomers, of methyl methacylate.

In addition, these mixtures for the preparation of polymethylmethacrylates can comprise further (meth)acrylates which arecopolymerizable with methyl methacrylate. The expression (meth)acrylateincludes methacrylates and acrylates, and mixtures of the two.

These monomers are also known. These include, inter alia,(meth)acrylates, which are derived from saturated alcohols, such as, forexample, methyl acrylate, ethyl(meth)acrylate, propyl(meth)acrylate,n-butyl(meth)acrylate, isobutyl(meth)acrylate tert-butyl(meth)acrylate,pentyl(meth)acrylate and 2-ethylhexyl(meth)acrylate;

(meth)acrylates which are derived from unsaturated alcohols, such as,for example, oleyl(meth)acrylate, 2-propynyl(meth)acrylate,allyl(meth)acrylate, vinyl(meth)acrylate;

Aryl(meth)acrylates, such as benzyl(meth)acrylate orphenyl(meth)acrylate, where the aryl radicals may in each case beunsubstituted or substituted up to four times;

cycloalkyl (meth)acrylates, such as 2-vinylcyclohexyl(meth)acrylate,bornyl(meth)acrylate;

hydroxyalkyl(meth)acrylates, such as 3-hydroxypropyl(meth)acrylate,3,4-dihydroxybutyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate,2-hydroxypropyl(meth)acrylate;

glycol di(meth)acrylates, such as 1,4-butandiol(meth)acrylate,(meth)acrylates of ether alcohols, such astetrahydrofurfuryl(meth)acrylate, vinyloxyethoxyethyl(meth)acrylate;

amides and nitriles of (meth)acrylic acid, such asN-(3-dimethylaminopropyl)(meth)acrylamide,N-(diethylphosphono)(meth)acrylamide,1-methacryloylamido-2-methyl-2-propanol; sulphur-containingmethacrylates, such as ethylsulphinylethyl(meth)acrylate,4-thiocyanatobutyl(meth)acrylate, ethylsulphonylethyl(meth)acrylate,thiocyanatomethyl(meth)acrylate, methylsulphinylmethyl(meth)acrylate,bis((meth)acryloyloxyethyl)sulphide;

polyvalent(meth)acrylates, such as trimethyloylpropanetri(meth)acrylate.

As well as the (meth)acrylates listed above, the compositions to bepolymerized can also have further unsaturated monomers which arecopolymerizable with methyl methacrylate and the abovementioned(meth)acrylates.

These include, inter alia, 1-alkenes, such as 1-hexene, 1-heptene;branched alkenes, such as, for example, vinylcyclohexane,3,3-dimethyl-1-propene, 3-methyl-1-diisobutylene, 4-methyl-1-pentene;

acrylonitriles; vinyl esters, such as vinyl acetate; styrene,substituted styrenes with an alkyl substituent in the side chain, suchas, for example, α-methylstyrene and α-ethylstyrene, substitutedstyrenes with an alkyl substituent on the ring, such as vinyltoluene andp-methylstyrene, halogenated styrenes, such as, for example,monochlorostyrenes, dichlorostyrenes, tribromostyrenes andtetrabromostyrenes;

heterocyclic vinyl compounds, such as 2-vinylpyridine, 3-vinylpyridine,2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine,2,3-dimethyl-5-vinylpyridine, vinylpyridimidine, vinylpiperidine,9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole,2-methyl-l-vinylimidazole, N-vinylpyrrolidone, 2-vinylpyrrolidone,N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam,N-vinylbutyrolactam, vinyloxolane, vinylfuran, vinylthiophene,vinylthiolan, vinylthiazoles and hydrogenated vinylthiazoles,vinyloxazoles and hydrogenated vinyloxazoles;

vinyl and isoprenyl ethers;

maleic acid derivatives, such as, for example, maleic anhydride,methylmaleic anhydride, maleinimide, methylmaleinimide; and dienes, suchas, for example, divinylbenzene.

In general, these comonomers are used in an amount of from 0 to 60% byweight, preferably 0 to 40% by weight and particularly preferably 0 to20% by weight, based on the weight of the monomers, where the compoundscan be used individually or as a mixture.

The polymerization is generally started using known free-radicalinitiators. Preferred initiators include, inter alia, the azo initiatorsknown throughout the specialist field, such as AIBN and1,1-azobiscyclohexanecarbonitrile, and peroxy compounds, such as methylethyl ketone peroxide, acetylacetone peroxide, dilauryl peroxide,tert-butyl per-2-ethylhexanoate, ketone peroxide, methyl isobutyl ketoneperoxide, cyclohexanone peroxide, dibenzoyl peroxide, tert-butylperoxybenzoate, tert-butyl peroxyisopropyl-carbonate,2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane, tert-butylperoxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate,dicumyl peroxide, 1,1-bis(tert-butylperoxy)cyclohexane,1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, cumylhydroperoxide, tert-butyl hydroperoxide,bis(4-tert-butylcyclohexyl)peroxydicarbonate, mixtures of two or more ofthese specified compounds with one another, and mixtures of thesespecified compounds with unspecified compounds which can likewise formfree radicals.

These compounds are often used in an amount of from 0.01 to 10% byweight, preferably from 0.5 to 3% by weight, based on the weight of themonomers.

In this connection, it is possible to use different poly(meth)acrylateswhich differ, for example, in their molecular weight or in the monomercomposition.

Furthermore, the polymethyl methacrylate shaped bodies can comprisefurther polymers in order to modify the properties. These include, interalia, polyacrylonitriles, polystyrenes, polyethers, polyesters,polycarbonates and polyvinyl chlorides. These polymers can be usedindividually or as a mixture, where also copolymers which can be derivedfrom the abovementioned polymers.

The plastic substrates according to the invention can, for example, beprepared from moulding materials of the abovementioned polymers. In thisconnection, use is generally made of thermoplastic moulding processes,such as extrusion or injection moulding.

The weight-average of the molecular weight M_(w) of the homopolymersand/or copolymers to be used according to the invention as mouldingmaterial for the preparation of the plastic substrates can vary withinwide ranges, the molecular weight usually being matched to the intendeduse and the processing method of the moulding material. However, it isgenerally in the range between 20 000 and 1 000 000 g/mol, preferably 50000 to 500 000 g/mol and particularly preferably 80 000 to 300 000g/mol, without being limited by this. This parameter can be determined,for example, by means of gel permeation chromatography.

Furthermore, the plastic substrates can be produced by casting chamberprocesses. In this, suitable (meth)acrylic mixtures are, for example,placed into a mould and polymerized. Such (meth)acrylic mixturesgenerally have the above-described (meth)acrylates, in particular methylmethacrylate.

Furthermore, the (meth)acrylic mixtures of the above-describedcopolymers and, particularly for adjusting the viscosity, polymers, inparticular, poly(meth)acrylates, may be present.

The weight-average of the molecular weight M_(w) of the polymers whichare prepared by casting chamber processes is generally higher than themolecular weight of polymers which are used in moulding materials. Thisgives rise to a number of known advantages. In general, the weightaverage of the molecular weight of polymers which are prepared bycasting chamber processes is in the range from 500 000 to 10 000 000g/mol, without being limited by this.

According to a particular embodiment of the present invention, thematrix of the polymethyl methacrylate shaped body has at least 70%,preferably at least 80%, and particularly preferably at least 90% byweight, based on the weight of the polymethyl methacrylate shaped body,of polymethyl methacrylate.

The polymethyl methacrylate shaped body comprises 0.005 to 0.4% byweight, in particular 0.005 to 0.1% by weight, preferably 0.01 to 0.04%by weight, based on the total weight of the polymethyl methacrylateshaped body, of at least one triazine compound according to formula (I)

in which

-   -   R is halogen, for example fluorine, chlorine, bromine or iodine,        C₁-C₂₂-alkyl, C_(I)-C₂₂-alkoxy, C_(I)-C₂₂-hydroxyalkoxy,        C_(I)-C₂₂-alkoxyalkyl, —NHR₁—, —N(R¹)₂, or a radical of the        formula (Ia)    -   X¹, X² and X³,        -   independently of one another, are —CONHR¹, —NR²R³, —SO₂R⁴,            —CN, —COR⁵ or —COOR⁶, in which        -   R¹ is hydrogen, C₁-C₂₂-alkyl, C₆-C₂₀-aryl, C₇-C₂₀-aralkyl,            C₅-C₈-cycloalkyl, or a radical of the formula (Ib)            -   in which            -   A₁ is C_(I)-C₈-alkyl, C₅-C₆-cycloalkyl, C₆-C₂₀-aryl,                C₇-C₂₀-aralkyl;            -   and            -   m₁is 1 to 10,        -   R² and R³, independently of one another, are hydrogen,            C_(I)-C₂₂-alkyl, C₆-C₈-cycloalkyl, C₆-C₂₀-aryl,            C₇-C₂₀-aralkyl, a radical of the formula (Ib) or a radical            of the formula —COR¹;        -   R⁴ is hydrogen, C_(I)-C₂₂-alkyl, C₆-C₈-cycloalkyl,            C₆-C₂₀-aryl, C₇-C₂₀-aralkyl, a radical of the formula (Ib)            or a radical of the formula —NR²R³;

R⁵ and R⁶, independently of one another, are hydrogen, C_(I)-C₂₂-alkyl,C₆-C₈-cycloalkyl, C₆-C₂₀-aryl, C₇-C₂₀-aralkyl or a radical of theformula (Ib);

-   -   X⁴, X⁵ and X⁶, independently of one another, are hydrogen or        hydroxyl.

According to a particular aspect of the present invention, triazinecompounds are used which can be represented by formula (II)

in which the radicals X¹, X², X³ have the meanings given above.

According to a particular embodiment of the present invention, triazinecompound are used which can be represented by formula (III)

in which the radicals R⁷, R⁸ and R⁹, independently of one another, areC_(I)-C₂₂-alkyl.

The alkyl radicals according to the abovementioned formulae (I) to (III)may be linear or branched. Furthermore, these radicals may havesubstituents, for example halogen atoms. Preferred straight-chain andbranched C_(I)-C₂₂-alkyl include, for example, methyl, ethyl, propyl,isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, 2-ethylbutyl,n-pentyl, isopentyl, 1-methylpentyl, 1,3-dimethylbutyl, n-hexyl,1-methylhexyl, n-heptyl, isoheptyl, 1,1,3,3-tetramethylbutyl,1-methylheptyl, 3-methylheptyl, n-octyl, 2-ethylhexyl,1,1,3-trimethylhexyl, 1,1,3,3-tetramethylpentyl, nonyl, decyl, undecyl,1-methylundecyl, dodecyl, 1,1,3,3,5,5-hexamethylhexyl, tridecyl,tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl or eicosyl.

The alkoxy radicals according to the abovementioned formulae (I) and(II) may be linear or branched. Furthermore, these radicals may havesubstituents, for example halogen atoms.

Examples of straight-chain and branched C_(I)-C₂₂-alkoxy are, forexample, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy,sec-butoxy, tert-butoxy, pentoxy, isopentoxy, n-heptyloxy, n-octyloxy,isooctyloxy, n-nonyloxy, isononyloxy, decyloxy, n-dodecyloxy,heptadecyloxy octadecyloxy or eicosyloxy.

Preferred cycloalkyl groups include the cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl and the cyclooctyl group, which areoptionally substituted by branched or unbranched alkyl groups.

Preferred cycloalkoxy groups include cycloalkoxy groups whosehydrocarbon radical is one of the abovementioned preferred cycloalkylgroups.

The aryl radicals may be optionally substituted by one or moreC₁-C₄-alkyl or alkoxy radicals. Examples of C₆-C₂₀-aryl are, inparticular, phenyl, naphthyl and biphenylyl.

The aralkyl radicals may be optionally substituted by one or more C₁— toC₄-alkyl or alkoxy radicals. Examples of C₇-C₂₀-aralkyl are benzyl,phenethyl, α-methylphenethyl or α,α-dimethylbenzyl.

“Alkylene” means a bivalent alkylene group having, preferably, 1 to 5,in particular 2 to 4, carbon atoms. These radicals include, inter alia,methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene,pentylene, 2-ethylpropylene.

Particular preference is given to using the triazine compound which canbe represented by formula (IV)

The compounds according to the above formulae and the preparationthereof are known per se and are described, for example, in EP-A 0 818450.

The compound according to formula (IV), bis(2-ethylhexyl)4,4′-[[6-[[4-[[1,1-dimethylethyl)-amino]carbonyl]phenyl]amino]-1,3,5-triazine-2,4-diyl]-diimino]bisbenzoacetate,can be obtained commercially from Ciba under the trade name ®UvasorbHEB.

Furthermore, the polymethyl methacrylate shaped body can comprisefurther known additives, their amount, however, being restricted to theintended use of the tanning aids according to the invention. Theseinclude, inter alia, antistatics, antioxidants, mould-release agents,flame retardants, lubricants, dyes, flow improvers, fillers, lightstabilizers, UV absorbers and organic phosphorus compounds, such asphosphites or phosphonates, pigments, anti-weathering agents andplasticizers.

Preferred additives include dyes which, dissolved in methyl methacrylateat a concentration of 0.01% by weight, display a transmission at 350 nmof at least 30%. Such dyes are known per se and are available, forexample, under the trade name ®Makrolex blue RR, ®Makrolex violet B,®Makrolex violet 3R, ®Makrolex green 5B, ®Makrolex green G, from Bayer,®Sandoplast blue 2B, ®Sandoplast red BB, and ®Sandoplast green G fromClariant, ®Mikrolit violet BK from Ciba.

Furthermore, preferred additives include IR absorbers. These include,inter alia, IR-Absorber 2052 from Bayer.

Furthermore, the polymethyl methacrylate shaped body can comprisespherical particles. For the purposes of the present invention, the termspherical means that the particles preferably have a ball-like shape, itbeing obvious to the person skilled in the art that, due to thepreparation methods, particles with a different shape may also bepresent, or that the shape of the particles can deviate from the idealball shape.

Accordingly, the term spherical means that the ratio of the largestdimension of the particles to the smallest dimension is at most 4,preferably at most 2, these dimensions in each case being measuredthrough the centre of gravity of the particles. Preferably at least 70%,particularly preferably at least 90%, based on the number of particles,are sperical.

The particles preferably have an average diameter (weight-average) inthe range from 5 to 50 μM, preferably in the range from 8 to 25 μm. Morefavourably, 75% of the particles are in the range from 5 to 35 μm.

These particles may, for example, be made of inorganic materials, inparticular of BaSO₄ or plastic, preference being given to plasticparticles. In this connection, the refractive index of the particles hasa refractive number no measured at the Na-D line (589 nm) and at 20° C.which differs from the refractive number no of the matrix plastic by0.02 to 0.2 unit.

The spherical plastic particles preferably comprise crosslinkedpolystyrene and/or crosslinked poly(meth)acrylates.

Mixtures from which the plastic particles are prepared particularlypreferably have at least 80% by weight of styrene and at least 0.5% byweight of divinylbenzene.

The preparation of crosslinked plastic particles is known in thespecialist field. For example, the scatter particles can be prepared byemulsion polymerization, as described, for example, in EP-A 342 283 orEP-A 269 324, very particularly preferably by polymerization in organicphase, as described, for example, in German Patent Application P 43 27464.1, where, in the case of the last-mentioned polymerizationtechnique, particularly narrow particle size distributions or, putanother way, particularly small deviations of the particle diametersfrom the average particle diameter, arise.

The polymethyl methacrylate shaped body can comprise, for example, 2 to50% by weight, preferably 4 to 10% by weight, of particles which developa scattering effect.

As a result of this, a reduction in the dazzling effect by solarirradiation can surprisingly be achieved without tanning of the skinbeing impaired too much. This preferred embodiment of the tanning aidaccording to the invention is particularly suitable for applications inwhich a dazzling effect of the sun is to be reduced.

According to a particular aspect of the present invention, thepolymethyl methacrylate shaped body has an impact strength of at least20 kJ/m² measured in accordance with DIN 53453 (standard test piece). Toimprove this mechanical property, known impact-resistance modifiers inparticular can be used.

Preferred impact-resistant moulding materials which can be used toproduce the polymethyl methacrylate shaped body comprise 1 to 30,preferably 2 to 20, particularly preferably 3 to 15, in particular 5 to12, % by weight of an impact-resistance modifying agent, whichrepresents an elastomer phase of crosslinked polymer particles.

The impact-resistance modifying agent can be obtained in a manner knownper se by bead polymerization or by emulsion polymerization.

Preferred impact-resistance modifying agents represent crosslinkedparticles with an average particle size in the range from 50 to 1 000nm, preferably 60 to 500 nm and particularly preferably 80 to 120 nm.

Particles of this type can be obtained, for example, by the free-radicalpolymerization of mixtures which generally at least 40% by weight,preferably 50 to 70% by weight, of methyl methacrylate, 20 to 80% byweight, preferably 25 to 35% by weight, of butyl acrylate, and 0.1 to 2%by weight, preferably 0.5 to 1% by weight, of a crosslinking monomer,e.g. a multifunctional (meth)acrylate, such as, for example, allylmethacrylate and comonomers which can be copolymerized with theabovementioned vinyl compounds.

The preferred comonomers include, inter alia,C₁-C₄-alkyl(meth)acrylates, such as ethyl acrylate or butylmethacrylate, preferably methyl acrylate, or other vinylicallypolymerizable monomers, such as, for example, styrene. The mixtures forthe preparation of the abovementioned particles may preferably comprise0 to 10% by weight, preferably 0.5 to 5% by weight, of comonomers.

Particularly preferred impact strength modifying agents are polymerparticles which have a two-layer, particularly preferably a three-layer,core-shell construction. Such core-shell polymers are described, interalia, in EP-A 0 113 924, EP-A 0 552 351, EP-A 0 465 049 and EP-A 0 683028.

Particularly preferred impact strength modifiers based on acrylaterubber have, inter alia, the following construction:

-   -   Core: Polymer with a methyl methacrylate fraction of at least        90% by weight, based on the weight of the core.    -   Shell 1: Polymer with a butyl acrylate fraction of at least 80%        by weight, based on the weight of the first shell.    -   Shell 2: Polymer with a methyl methacrylate fraction of at least        90% by weight, based on the weight of the second shell.

As well as comprising the specified monomers, the core and the shellsmay in each case comprise further monomers. These have been describedabove, particularly preferred comonomers having a crosslinking effect.

For example, a preferred acrylate rubber modifier may have the followingconstruction:

-   -   Core: Copolymer of methyl methacrylate (95.7% by weight), ethyl        acrylate (4% by weight) and allyl methacrylate (0.3% by weight)    -   S1: Copolymer of butyl acrylate (81.2% by weight), styrene        (17.5% by weight) and allyl methacrylate (1.3% by weight)    -   S2: Copolymer of methyl methacrylate (96% by weight) and ethyl        acrylate (4% by weight)

The ratio of core to shell(s) in the acrylate rubber modifier may varywithin wide ranges. The weight ratio of core to shell C/S is preferablyin the range from 20:80 to 80:20, preferably from 30:70 to 70:30 tomodifiers with one shell, and the ratio of core to shell 1 to shell 2C/S1/S2 is in the range from 10:80:10 to 40:20:40, particularlypreferably from 20:60:20 to 30:40:30 in the case of modifiers with twoshells.

The particle size of the core-shell modifiers is usually in the rangefrom 50 to 1 000 nm, preferably 100 to 500 nm and particularlypreferably from 150 to 450 nm, without being limited thereby.

According to a particular embodiment, the polymethyl methacrylate shapedbody has a E modulus of at least 2 800 N/mm², preferably at least 3 300N/mm² according to ISO 527/2.

The thickness of the polymethyl methacrylate shaped body can be within awide range depending on the intended use. In general, this shaped bodyhas a to 20 mm.

The surface of the tanning aids may appear shiny or matt. According to aparticular embodiment, the tanning aids may be equipped with a satinsurface.

The size of the tanning aid can be adapted to the requirements. Thus,for example, roofs may be several 100 m² in size or smaller screens maycomprise nearly 1 to 2 m².

The invention is illustrated in more detail by Example 1 below withoutthe invention being limited to this example.

EXAMPLE 1

A polymethyl methacrylate panel with a thickness of 3 mm was produced ina casting process. For this, 994.208 g of syrup (mixture of methylmethacrylate/polymethyl methacrylate with 8 to 10% conversion), 0.039 gof ®Mikrolit violet BK, 0.03 g of Solvaperm red BB, 0.200 g of ®UvasorbHEB obtainable from Ciba Geigy and 0.55 g of 2,2-azodi(isobutyronitrile)(AIBN, from Akzo Nobel were mixed and poured into a casting glass mould.This mould was heated at 77° C. for 150 minutes.

The panel obtained in this way had a UV transmission at 380 nm of morethan 60% and at 330 nm a transmission of less than 0.1%. The calculatedeffective radiation intensity was 4.79 mW/m².

The effective irradiation intensity can be calculated by the erythemafunction, which is expressed the efficiency of ultraviolet radiation forproducing reddening of human skin. The evaluation is carried out bymultiplying the transmitted irradiation spectrum by the erythemafunction.

The irradiation spectrum arises from the solar spectrum in accordancewith standard DIN 67501. Integration of the evaluated spectrum over thewavelength gives the effective irradiation intensity, where theeffectiveness refers to the efficacy for producing sunburn. The originalsolar spectrum has an effective irradiation intensity of about 250.9mW/m².

1-15. (canceled)
 16. A tanning aid, characterized in that the tanningaid comprises a polymethyl methacrylate shaped body, where thetransparency of the polymethyl methacrylate shaped body at 380 nm is atleast 40%, and the polymethyl methacrylate shaped body comprises 0.005to 0.4% by weight, based on the weight of the polymethyl methacrylateshaped body, of at least one triazine compound according to formula (I)

in which R is halogen, C₁-C₂₂-alkyl, C₁-C₂₂-alkoxy,C_(I)-C₂₂-hydroxyalkoxy, C_(I)-C₂₂-alkoxyalkyl, —NHR₁—, —N(R¹)₂, or aradical of the formula (Ia)

X¹, X² and X³, independently of one another, are —CONHR¹, —NR²R³,—SO₂R⁴, —CN, —COR⁵ or —COOR⁶; R¹ is hydrogen, C₁-C₂₂-alkyl, C₆-C₂₀-aryl,C₇-C₂₀-aralkyl, C₅-C₈-cycloalkyl, or a radical of the formula (Ib)

in which A₁ is C₁-C₈-alkyl, C₅-C₆-cycloalkyl, C₆-C₂₀-aryl,C₇-C₂₀-aralkyl; and m₁ is 1 to 10, R² and R³, independently of oneanother, are hydrogen, C₁-C₂₂-alkyl, C₆-C₈-cycloalkyl, C₆-C₂₀-aryl,C₇-C₂₀-aralkyl, a radical of the formula (Ib) or a radical of theformula —COR¹; R⁴ is hydrogen, C₁-C₂₂-alkyl, C₆-C₈-cycloalkyl,C₆-C₂₀-aryl, C₇-C₂₀-aralkyl, a radical of the formula (Ib) or a radicalof the formula —NR²R³; R⁵ and R⁶, independently of one another, arehydrogen, C_(I)-C₂₂-alkyl, C₆-C₈-cycloalkyl, C₆-C₂₀-aryl, C₇-C₂₀-aralkylor a radical of the formula (Ib); X⁴, X⁵ and X⁶, independently of oneanother, are hydrogen or hydroxyl.
 17. The tanning aid according toclaim 16, characterized in that the at least one triazine compound canbe represented by formula (II)

in which the radicals X¹, X², X³ have the meaning given in claim
 16. 18.The tanning aid according to claim 16, characterized in that the atleast one triazine compound can be represented by formula (III)

in which the radicals R⁷, R⁸ and R⁹, independently of one another, areC_(I)-C₂₂-alkyl.
 19. The tanning aid according to claim 16,characterized in that the at least one triazine compound can berepresented by formula (VI)


20. The tanning aid according to claim 16, characterized in that thetanning aid comprises 0.01 to 0.04% by weight, based on the weight ofthe polymethacrylate shaped body, of the at least one triazine compound.21. The tanning aid according to claim 16, characterized in that theplastic shaped body additionally comprises dyes which, dissolved in MMAat a concentration of 0.01% by weight, exhibit a transmission of atleast 30% at 350 nm.
 22. The tanning aid according to claim 16,characterized in that the transparency of the polymethyl methacrylateshaped body at 400 nm is at least 30%.
 23. The tanning aid according toclaim 16, characterized in that the transparency of the polymethylmethacrylate shaped body at 330 nm is at most 30%.
 24. The tanning aidaccording to claim 16, characterized in that the ratio of transparencyof the polymethyl methacrylate shaped body at 400 nm to the transparencyat 330 nm is at least
 20. 25. The tanning aid according to claim 16,characterized in that the polymethyl methacrylate shaped body comprisesan IR absorber.
 26. The tanning aid according to claim 16, characterizedin that the polymethyl methacrylate shaped body has an impact resistanceof at least 20 kJ/m².
 27. The tanning aid according to claim 16,characterized in that the polymethyl methacrylate shaped body has athickness in the range from 1 to 200 mm.
 28. The tanning aid accordingto claim 16, characterized in that the polymethyl methacrylate shapedbody has an E modulus of at least 2,800 N/mm².
 29. The tanning aidaccording to claim 16, characterized in that the polymethyl methacrylateshaped body comprises spherical particles.